I've got this odd Colt barrel and I was wondering if anybody had any idea how it came to have the configuration it now has.  I got it off of ebay awhile ago and took a good look at it recently for project potential and I found some odd things.  It is stamped "C MP 5.56 NATO 1/9 HBAR", not so odd yet, but..................

1.  Neither the chamber nor the bore are chrome lined.  The barrel was sold to me as "new, unfired" and it looks that way.

2.  It hasn't had a FSB on it yet and it hasn't had a gas port drilled yet either.

3.  It has an M4 extension with the "4" stamp and everything.  The extension indexing pin is properly indexed to the barrel stamping.

4.  It has a date stamp of 9/97.  Now I read something here on ARFCOM that in the mid to late 90's that Colt stopped chrome lining the bores on HBARs, but I thought they still chromed the chamber.

I guess I'll put it together with a receiver, headspace check it and see if it shoots well, but I am sort of curious how a barrel can end up in such an odd configuration.  Thanks for any thoughts and info.

Stamping doesnt say chrome, so there should be no chrome...

Quoted: Stamping doesnt say chrome, so there should be no chrome...

I have a 20" gov't profile barrel stamped "C MP 5.56 NATO 1/7" that has a chrome bore and chamber, just like M16s do and a M4 barrel with the same stampings and it also has chrome bore and chamber.  Colt hasn't stamped "CHROME BORE" or anything like that on their barrels for a long time.

None of the one I had were chromed, YMMV though as I am in now way a expert.. I do know that a lot of folks get confused by the "C" which means COLT and not Chrome..

Colt hasn't stamped "CHROME BORE" or anything like that on their barrels for a long time.

Not true. I just bought a NIB LEO that has "Chrome Bore" stamped in the bbl, the bbl date is 6/04...

Quoted: None of the one I had were chromed, YMMV though as I am in now way a expert.. I do know that a lot of folks get confused my the "C" which means COLT and not Chrome.. Some one else will chime in.. I would like to know too...

"C" means Colt
"B" means Bushmaster
"E" means EMCO
"FNMI" means FN

You get my point.

I bought a similar barrel from SAWLESALES, though Ken & Tina verified that it was chrome lined in both bore and chamber prior to purchase.  Mine has the same markings, don't know why the one you picked up lacks the chroming and gas port.  They informed me that these barrels were a rare production, for LE/MIL.  I don't beleive there is any rhyme nor reason with COLT in regards to barrel markings and what is chromed or not chromed.  Every time someone says there is a standard that identifies which barrels are chromed or not, someone proves that theory out the window.  It is interesting to say the least.

Send it back to COLT and tell them to finish the job!  

Quoted: SAWLESALES, though Ken & Tina

I'd suggest asking them.  They probably know more about Colt than Colt does.  And that's not a joke.

BTT.  Appreciate the info and suggestions so far.  Any other opinions?  I'm hoping it isn't some type of reject, but the MP on the barrel should mean it is mag particle tested and proof fired.  No obvious defects inside or out.

I'm going to build something with it, just don't know what yet.  Must get my "Evil Tinkerer" mind going on this one.  First, drill/ream the gas port, second, thread the muzzle, third...................................now this is where all the evil begins................................

OH, BTW, I was digging through my "barrel stash" and I found another one of these, except this one is a preban variety with small lettered stampings.  Appears this one isn't chrome lined on either chamber or bore either, but I'm going to have to give it a thorough cleaning to make sure.  No date stamp on this one.